C004A: Brake Lining Wear Sensor (Subfault)

What it means

This code identifies a fault associated with the brake lining wear sensor. The specific failure depends on the diagnostic subtype.

At a glance

• Usually lights the ABS or stability-control warning light

How it works

The brake lining wear sensor monitors brake pad or lining wear and signals when service is due. This subfault code indicates a problem associated with that sensing system; the subtype helps distinguish actual wear from a sensor or circuit fault.

Common causes

Most likely first.

1. Worn brake pads
2. Brake lining wear sensor damaged or open
3. Sensor wiring or connector fault
4. Incorrect sensor installation

Symptoms

• Brake lining wear warning may appear

How to diagnose it

1. Read the subtype and freeze-frame data to learn whether the system detected wear, an open circuit, or another sensor fault.
2. Inspect the brake pads or linings at the wheels fitted with wear sensors and compare remaining material with the manufacturer's service limit.
3. Check that each wear sensor is seated correctly and has not been cut, pulled loose, or damaged during brake work.
4. Inspect sensor connectors and wiring along the wheel area for corrosion, breaks, or rubbing damage.
5. If the pads and wiring look sound, test sensor continuity and the module input as specified by the manufacturer.

Common fixes

• Replace worn pads or linings and fit new wear sensors where required.
• Correct an improperly seated or incorrectly routed wear sensor.
• Repair damaged sensor wiring or connector terminals.
• Replace a failed wear sensor.
• Repair the control module only if its input is confirmed faulty.

Can I keep driving?

This code may indicate that brake pads are worn, even if braking still feels normal. Check pad condition promptly and avoid delaying service; stop driving if braking performance changes or grinding is heard.